A combination of unhealthy habits, including poor diet, too much screen time, and lack of exercise, put adolescents at a significantly higher risk of experiencing both anxiety and depression, according to a new study published in . BMC Psychiatry.
Researchers have long known that personal habits, such as lack of exercise and sleep deprivation, can affect mental health. However, in real life, these behaviors rarely occur in isolation. Teens who skip meals, spend too much time looking at screens, and lack sleep often do all of these things at once. This “clustering” of unhealthy habits is less studied, especially in relation to complex mental health conditions.
To address this gap, researchers wanted to understand whether patterns of multiple unhealthy behaviors could predict which adolescents are at highest risk of developing both anxiety and depression.
A research team led by Xiaoyan Wu from China’s Anhui Medical University followed 6,656 young people (average age 14 years, 52% female) for one year. Students completed a smartphone-based self-report survey that assessed 15 lifestyle behaviors, including diet, physical activity, sleep patterns, alcohol consumption, suicidal behavior, and screen time, as well as symptoms of anxiety and depression.
The researchers used statistical modeling to categorize participants into four lifestyle categories. Those with low risk (24%), those with poor eating habits (40%), those with high screen time and sedentary behavior (22%), and those with multiple unhealthy behaviors (14%). We then tracked how these baseline patterns were associated with mental health outcomes one year later.
The results were amazing. Teens in the sedentary and screen time group were about 50% more likely to experience both anxiety and depression. Meanwhile, the group that engaged in multiple unhealthy behaviors was more than three times as likely to develop these comorbid conditions.
The sheer number of unhealthy habits was also important, and a clear dose-response pattern emerged. The more unhealthy behaviors a teen engages in, the more likely they are to develop co-occurring mental health problems. Adolescents with four to six unhealthy behaviors were about 40% more likely to suffer from both anxiety and depression, and those with seven or more had almost three times the risk.
Importantly, these results held true even after accounting for other factors such as family income, number of friends, and family history of depression, and the pattern was consistent for both boys and girls. Furthermore, when the researchers reran the data by excluding suicidal behavior, which essentially overlaps with depression severity, they found that the clustering of poor diet, lack of exercise, and sleep deprivation alone still strongly predicted the development of the combined condition.
This study highlights that unhealthy habits don’t just add up, they can interact and reinforce each other, leading to compounding effects on mental health. For example, excessive screen time can disrupt your sleep and affect your mood and energy levels, while poor eating habits can further worsen your mental health.
“These results highlight the need to monitor adolescents with high-risk behavioral profiles. Targeted lifestyle modifications may be an effective strategy for early prevention and intervention of co-occurring mental health disorders in adolescents,” concluded Wu et al.
Despite its strengths, this study has several limitations. This study only included students currently attending school, so the results may not apply to all adolescents. Mental health symptoms were also self-reported rather than clinically diagnosed, which could introduce bias. Additionally, unmeasured factors such as childhood stress may have influenced the results.
The study, “Association of anxiety and depression comorbidity and clustered unhealthy lifestyle behaviors in adolescents,” was authored by Wanyu Che, Ziyan Ruan, Shuman Tao, Meng Wang, Yuxuan Cao, Yaqian Niu, Yuming Chen, Tangjun Jiang, Tingting Li, Liwei Zou, Fangbiao Tao, and Xiaoyan Wu.
